**2. Geological setting and characteristics of three ice caves in China**

#### **2.1 Ningwu ice cave**

Ningwu ice cave (38°57′N, 112°10′E; 2121 m above sea level (asl)) is called "ten thousand years ice cave" by local people. It is located in the shaded slope of Guancen Mountain, Ningwu County, and Shanxi Province. The host rock consists of Ordovician Majiagou limestone, dolomitic limestone, argillaceous dolomite, and thin brecciated limestone and is densely fractured [22].

As a part of Ningwu National Geological Park, Ningwu ice cave is an important tourist attraction. Above 1500 visitors enter the cave per day from May to October. It has only a single entrance. People can walk into the inside of the cave by wooden spiral stairs. Ice covers the host rock almost completely. Ice stalactites and ice stalagmites can be found in all parts of the cave (**Figure 1a**).

In order to investigate the fine geometry of Ningwu ice cave, a classic geophysical exploration (using magnetotelluric measurement) was carried out and produced a high-resolution two-dimensional vertical cross-section of the ice cave [22] (**Figure 1b**). **Figure 1b** illustrates a bowling pin-shaped room, and the cave space is about 85 m depth. The widest part is in the middle of the cave with a width of 20 m.

The outside of Ningwu ice cave keeps a temperate climate. From June to September, the mean air temperature is about 14.6°C, and the average annual air temperature is 2.3°C [20]. The nearest meteorological station to Ningwu ice cave is Wuzhai station (about 320 m lower than Ningwu ice cave), at which the daily temperature was measured continuously from 1957 to 2008. We averaged the observational air temperature at Wuzhai meteorological station to get the annual temperature and then derived the mean annual temperature at Wuzhai station. The difference between the average annual air temperature at Ningwu ice cave and that at Wuzhai station can be calculated. Finally, we obtained the annual temperature variation outside Ningwu ice cave through reducing the annual temperature at Wuzhai station by the difference.

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*A Review of Chinese Ice Caves*

**2.2 Zibaishan ice cave**

**Figure 1.**

width above 25 m.

limestone.

**2.3 Wudalianchi ice cave**

palace) ice cave.

Zibaishan ice cave (33.7°N, 106.68°E; 2450 m asl) was found in August 2015, and it is located in the shaded slope of Zibai Mountain, Liuba County, Shanxi Province. Fieldwork was conducted in May 2016, and then the geometry and temperature profile of the ice cave was measured. The measurements are shown in **Figure 2a**. The cave space has a depth of about 90 m. The widest part is at the bottom with a

*2D geometry of Ningwu ice cave based on geophysical exploration [22] (a) and its interior (b).*

Zibaishan ice cave, located in Zibaishan National Forest Park, is also a major tourist attraction. Most of the tourists only visited the opening of the ice cave, and a few experienced adventurers with professional climbing equipment could reach the interior of the ice cave. Consequently, Zibaishan ice cave maintained better natural environments (because of little artificial effects) than Ningwu ice cave. Ice deposits of the ice cave mainly included two parts: (1) ice cone which has a diameter of 25 m and a height of 16 m (**Figure 2b**) and (2) ice stalactites (**Figure 2c**). Ice deposits covered wall rocks of the ice cave partially. The host rock consists of

The outside of Zibaishan ice cave belongs to the warm temperate zone and humid monsoon section. The external annual mean air temperature is 11.5°C, and the frost-free period is 214 days per year [23]. Generally, ice deposits could not be preserved under such a temperate environment. Therefore, there must be some

There are two ice caves at Wudalianchi National Geological Park (48.647°, 126.25°, 400 m asl), Heilongjiang Province: one is Bailong (means white dragon; also named Dixiabinghe) ice cave, and another is Shuijinggong (means crystal

We conducted simple field work on Bailong ice cave in August 2012. The host rock is basalt. Dense fractures developed near the entrance. Basaltic pillars can be seen within the cave. The farthest distance we can reach is about 270 m from

special cooling mechanisms of Zibaishan ice cave.

*DOI: http://dx.doi.org/10.5772/intechopen.89178*

*Earth Crust*

useful for ice cave studies.

stability during its cooling process.

**2.1 Ningwu ice cave**

atmospheric conditions [15, 16]. In temperate karstic natural conditions, interpretation of the existence of subsurface ice deposits represents probably the most severe test for models of the magnitude and direction of heat and mass transfers induced by cave air circulation [9]. In theory and application (mathematics and engineering), the finite element method (FEM) and the finite difference method (FDM) are classical methods for finding approximate solutions of partial differential equations, which governed physical processes (including heat transfer). The details of FEM and FDM can be found in many textbooks [17, 18]. These methods would be

Since Ningwu ice cave was found, ice cave studies began in 1998 in China. Ningwu ice cave in Shanxi Province has been broadly reported during the past decade [19, 20], but little was known about the physical processes controlling the formation and preservation of permanent subsurface ice deposits under temperate climate conditions [21]. In addition to, basaltic cave stability is significant for ice preservation. FEM was applied to investigate the energy exchange of Ningwu ice cave and then quantitatively interpret the formation and preservation mechanism of the ice deposit. Thermal-elastic modeling was conducted to study lava tube

**2. Geological setting and characteristics of three ice caves in China**

Ningwu ice cave (38°57′N, 112°10′E; 2121 m above sea level (asl)) is called "ten thousand years ice cave" by local people. It is located in the shaded slope of Guancen Mountain, Ningwu County, and Shanxi Province. The host rock consists of Ordovician Majiagou limestone, dolomitic limestone, argillaceous dolomite, and

As a part of Ningwu National Geological Park, Ningwu ice cave is an important tourist attraction. Above 1500 visitors enter the cave per day from May to October. It has only a single entrance. People can walk into the inside of the cave by wooden spiral stairs. Ice covers the host rock almost completely. Ice stalactites and ice

In order to investigate the fine geometry of Ningwu ice cave, a classic geophysical exploration (using magnetotelluric measurement) was carried out and produced a high-resolution two-dimensional vertical cross-section of the ice cave [22] (**Figure 1b**). **Figure 1b** illustrates a bowling pin-shaped room, and the cave space is about 85 m depth. The widest part is in the middle of the cave with a width

The outside of Ningwu ice cave keeps a temperate climate. From June to September, the mean air temperature is about 14.6°C, and the average annual air temperature is 2.3°C [20]. The nearest meteorological station to Ningwu ice cave is Wuzhai station (about 320 m lower than Ningwu ice cave), at which the daily temperature was measured continuously from 1957 to 2008. We averaged the observational air temperature at Wuzhai meteorological station to get the annual temperature and then derived the mean annual temperature at Wuzhai station. The difference between the average annual air temperature at Ningwu ice cave and that at Wuzhai station can be calculated. Finally, we obtained the annual temperature variation outside Ningwu ice cave through reducing the annual temperature at

thin brecciated limestone and is densely fractured [22].

stalagmites can be found in all parts of the cave (**Figure 1a**).

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Wuzhai station by the difference.

of 20 m.

**Figure 1.** *2D geometry of Ningwu ice cave based on geophysical exploration [22] (a) and its interior (b).*
